Device for overcoming alternating currents in direct-current circuits.



No. 708,|2|. v Patented Sept. 2, I902.

H. BBOCKELT.

DEVICE FOR ovascumma ALTERNATING GUBRENTS m DIRECT CURRENT cmcuns.

(Application filed Mar. 23, 1902,

(No Model.)

filed- I a. 4/425? w: Noams FEIERS co. nnormumo wnsmumou. u. c.

UNITED STATES PATENT OFFICE.

HERMANN BROOKELT, OF BERLIN, GERMANY.

DEVICE FOR OVERCOMING ALTERNATING CURRENTS lN DIRECT-CURRENT CIRCUITS.

SPECIFICATION forming part of Letters Patent No. 708,121, datedSeptember 2, 1902. 7 Application filed March 28, 1902. Serial No.100,382. (No model.)

To all whom it may concern.-

Be it known that I, HERMANN BRookELT, a subject of the German Emperor,residing in Berlin, in the Kingdom of Prussia, Germany, have inventedcertain new and useful Improvements in Devices for OvercomingAlternating Currents in Direct-Current Circuits, of which the followingis a specification.

My invention relates to means for destroying disturbing alternatingcurrents in the conductors of electric railroads working with directcurrent.

As is well known, the counter force which is generated in electromotorsdriven by direct current is not absolutely constant, but is variable.This counter electromotive force can be imagined as consisting of thesum of a uniform electromotive and arelativelysmaller electromotiveforce constantly alternating in direction. The alternating currentarising through the latter is the cause of telephone disturbances withelectric railroads working with a direct current.

My invention is illustrated by the annexed drawing, which is a diagramof the connections employed.

According to my invention a transformer is so arranged that the flow ofthe disturbing alternating currents into the external circuit isprevented by the primary winding (0 of the transformer 11, which windingis inserted in the working circuit, producing in its secondary winding0, which is connected in a shuntcircuit of the series motor d, a currentopposed to the generating-current and tending to overcome the latter inconsequence of temporal deviation, according to the well-known law ofLenz, on the common path of current through the motor cl. I If,therefore, effect and countereffect are equal, no alternating currentcan reach the external circuit. Such a condition of counterbalance isapproximately attainable, as experiment'shows.

The arrangement differs from an already well-known like arrangement of atransformer for removing the collateral noises in telephones in that thedisturbing alternating current inside the circuit of thetelephone-receivers is overcome, but not at the source itself.

The practical advantage of this arrangement over similar arrangementsfor the same purpose is that the self-induction with transformers ofproperly-chosen dimensions is not increased, so that vigorous sparkingbetween the sliding loop and the conductor is prevented, and thus rapidwear of the parts successfully avoided. The arrangement also differsfrom another well-known method, according to which the secondary windingof a transformer is connected to the exclusion of the field-magnets ofthe motor in shunt to the primary coil.

Having thus described my invention, what I claim as new, and desire tosecure byLetters Patent, is

In means for destroying the disturbing alternating current in theconductors of electric railroads worked with direct current, atransformer the primary winding of which is connected in the seriescircuit, and the secondary in a shunt-circuit to the motor, in suchmanner that on the common path through the motor, the alternatingcurrent generated by the latter flows in opposite direction to thecurrent produced in the secondary winding, for the purpose of removingthe former, substantially as described.

In testimony whereofl have hereunto signed my name in the presence oftwo subscribing witnesses.

HERMANN BROOKELT. lVitnesses:

ENRIQ UE VITTE, HENRY HASPER.

